Guide extension catheter

ABSTRACT

Guide extension catheters and related methods are disclosed. A guide extension catheter can comprise an elongate tube member and a lumenless push member. The push member can be eccentrically coupled to the tube member for slidably positioning the tube member within and partially beyond a distal end of a guide catheter. At least a proximal end portion of the push member can include a cross-section defined by an arcuate first surface and an opposing second surface. The first surface can engage an inner wall surface of the guide catheter along an arc length, and the second surface can be spaced furthest from the first surface at its center point. The first surface can have the same or substantially the same radius of curvature as the guide catheter&#39;s inner wall surface, and the second surface can be flat or substantially flat. This configuration of the push member can provide an advantageous blend of stiffness and flexibility, as well as space conservation through the guide catheter.

CLAIM OF PRIORITY

This patent document is a continuation of U.S. Non-Provisional patentapplication Se. No. 15/581,176, entitled “GUIDE EXTENSION CATHETER” andfiled on Apr. 28, 2017, which claims the benefit of priority under 35U.S.C. §119(e) to Brenizer et al., U.S. Provisional Patent ApplicationSer. No. 62/431,911, entitled “GUIDE EXTENSION CATHETER” and filed onDec. 9, 2016, and to Brenizer et al., U.S. Provisional PatentApplication Ser. No. 62/440,438, entitled “GUIDE EXTENSION CATHETER” andfiled on Dec.30, 2016, each of which is herein incorporated by referencein its entirety.

TECHNICAL FIELD

This patent document relates to medical devices. More particularly, butnot by way of limitation, the patent document relates to guide extensioncatheters for use with guide catheters.

BACKGROUND

A guide catheter can back-out and withdraw from a vessel's ostium orbranch when an interventional device, such as a guidewire, ballooncatheter, stent or stent catheter, is passed through it and advancedbeyond the guide catheter's distal end. This backing out of the guidecatheter can cause the operating physician to lose the ability tofurther distally advance the interventional device.

OVERVIEW

The present inventors recognize that there is a need to provideincreased back-up support to interventional devices and guide cathetersduring interventional procedures. A guide extension catheter can be usedin conjunction with a guide catheter to access discrete regions ofcoronary or peripheral vasculature and to facilitate accurate placementof interventional devices without guide catheter back-out from a vesselostium or branch of interest. The guide extension catheter can alsoprovide a means for delivering drugs or providing negative pressure toand from a treatment site. The present inventors further recognize thatthe interventional art would benefit from the availability of a guideextension catheter that can be effectively and efficiently urged througha guide catheter and have its distal end deep-seated into the vesselportion of interest without kinking or bending improperly, withoutreducing the device delivery area through the guide catheter, andwithout becoming entangled with a guidewire.

Guide extension catheters and related methods are disclosed in thispatent document. A guide extension catheter can comprise an elongatetube member and a lumenless push member. The push member can beeccentrically coupled to the tube member for slidably positioning thetube member within and partially beyond a distal end of a guide catheterand a vessel ostium of interest. At least a proximal end portion of thepush member can include a cross-section defined by an arcuate firstsurface and an opposing second surface. The first surface can engage aninner wall surface of the guide catheter along an arc length, and thesecond surface can be spaced furthest from the first surface at itscenter point. The first surface can have the same or substantially thesame radius of curvature as the guide catheter's inner wall surface, andthe second surface can be flat or substantially flat, for example. Thisconfiguration of the push member can provide an advantageous blend ofstiffness, flexibility and space conservation through the guidecatheter. The push member can include one or more means along its lengthto urge the push member to one side of the guide catheter's inner wallsurface, thereby providing a clear path through the guide catheter andinto the guide extension catheter for an interventional device.

These and other embodiments and features of the present guide extensioncatheters and related methods will be set forth, at least in part, inthe following Detailed Description. This Overview is intended to providenon-limiting embodiments of the present subject matter—it is notintended to provide an exclusive or exhaustive explanation of thedisclosed embodiments. The Detailed Description below is included toprovide further information about the present guide extension cathetersand methods.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals can be used to describe similar featuresand components throughout the several views. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in this patent document.

FIG. 1 illustrates a plan view of a guide catheter advanced through anaorta to an ostium of a coronary vessel.

FIG. 2 illustrates a plan view of a guide extension catheter, asconstructed in accordance with at least one embodiment, used inconjunction with a guide catheter for the delivery of an interventionaldevice into an occluded vessel for treatment.

FIG. 3 illustrates a side view of a guide extension catheter, asconstructed in accordance with at least one embodiment, partially withina sectioned guide catheter.

FIGS. 4-6 illustrate cross-sectional views along the length of a guideextension catheter's push member, as constructed in accordance with atleast one embodiment, within a guide catheter.

FIG. 7 illustrates a side view of a guide extension catheter, asconstructed in accordance with at least one embodiment, and aninterventional device partially within a sectioned guide catheter.

FIG. 8 illustrates a cross-sectional view of a guide extension catheter,as constructed in accordance with at least one embodiment, and aninterventional device within a guide catheter.

The drawings are not necessarily to scale. Certain features andcomponents may be shown exaggerated in scale or in schematic form, andsome details may not be shown in the interest of clarity andconciseness.

DETAILED DESCRIPTION

This patent document discloses guide extension catheters to be placedwithin guide catheters for providing support and guidance in a vesselwhen percutaneously advancing interventional devices, such asguidewires, balloon catheters, stents or stent catheters. A guideextension catheter is configured to be passed through a main lumen of aguide catheter so that its distal end portion can be extended past adistal end of the guide catheter and into the desired vessel while itsintermediate portions remain within the guide catheter. The guideextension catheter improves the ability of the guide catheter to remainseated in the desired vessel's ostium or branch during an interventionalprocedure.

It is believed that the present guide extension catheters will findgreat utility by interventional cardiologists performing percutaneoustransluminal coronary interventions. Although the remainder of thispatent document generally discusses and illustrates such uses, it shouldbe understood that the guide extension catheters can also be used fortreating other non-coronary diseased vessels or other hollow structures(e.g., biliary tract, ureter, etc.) throughout a patient's body whereinterventional devices are or can be employed.

Minimally-invasive cardiac interventions are utilized throughout theworld and include the use of a guidewire 112 and a guide catheter 102,as illustrated in FIG. 1. The guidewire 112 is an elongate,small-diameter member designed to navigate vessels to reach a diseasedsite or vessel segment of interest. Guidewires come in two basicconfigurations: solid steel or nitinol core wires and solid core wirewrapped in a smaller wire coil or braid. The guide catheter 102 is anelongate tube member defining a main lumen 104 along its length. Theguide catheter 102 can be formed of polyurethane, for example, and canbe shaped to facilitate its advancement to a coronary ostium 106 (orother region of interest within a patient's body). In the embodiment ofFIG. 1, a 4F, 5F, 6F, 7F or 8F guide catheter 102, where F is anabbreviation for the French catheter scale (a unit to measure catheterdiameter (1F=⅓ mm)), can be inserted at a femoral or radial artery andadvanced through an aorta 108 to a position adjacent to the ostium 106of a coronary artery 110.

In a typical procedure, the guidewire 112 is advanced through the arch114 of the aorta 108 to the ostium 106. The guide catheter 102 is thenpassed over the guidewire 112 until its distal end 116 is seated nearthe ostium 106. The diameter and rigidity of the guide catheter's distalend 116 oftentimes does not permit the device to be advanced beyond theostium 106 and into the coronary artery 110.

Maintaining the position of the guide catheter's distal end 116 at theostium 106 can facilitate the guidewire 112 or other interventionaldevice successfully reaching the diseased site (e.g., a stenotic lesion118) through its further distal advancement. With the guide catheter 102in position, force can be applied to the guidewire's proximal end topush the guidewire 112 to and beyond the lesion 118, and a treatingcatheter (optionally including a balloon or stent) can be passed overthe guidewire 112 to treat the site. The application of force to theguidewire 112 or the treating catheter can sometimes cause the guidecatheter 102 to dislodge from the ostium 106 of the coronary artery 110,and, in such instances, the guidewire or treating catheter must befurther distally advanced independently of the guide catheter'salignment and support to reach the lesion 118. This can occur in thecase of a tough stenotic lesion 118 or tortuous anatomy, where it isdifficult to pass the guidewire 112 or the treating catheter to andbeyond the lesion. A heart's intrinsic beat can also cause the guidecatheter's distal end 116 to lose its positioning or otherwise beshifted so that it no longer is positioned to align and support theguidewire 112 or the treating catheter into the portion of the coronaryartery 110 including the lesion 118.

As illustrated in FIG. 2, the present guide extension catheter 200 canimprove access to a coronary artery 210 and a stenotic lesion 218. Theguide extension catheter 200 can include a relatively flexible elongatetube member 220 and a push member 222 having a collective length that isgreater than a length of a guide catheter 202 (e.g., 130 cm-175 cm). Anouter diameter of the tube member 220 can be sized to permit insertionof its distal end portion 224 into a coronary artery or its branchescontaining the lesion 218, thereby providing alignment and support foran interventional device (e.g., a treating catheter) beyond the distalend 216 of the guide catheter 202 to the lesion and beyond. Theextension of the tube member 220 into the smaller-sized artery or branchalso serves to maintain the position of the guide catheter 202 at anartery's ostium 206 during operation.

The operating physician can advance the distal end portion 224 of thetube member 220 over a guidewire 212 and through and beyond the guidecatheter's distal end 216 into the coronary artery 210. A proximal endportion 226 of the tube member 220 can remain within the guide catheter202. The physician can then deliver the treating catheter over theguidewire 212, through a main lumen 204 of the guide catheter 202, andthrough a lumen 228 of the tube member 220 until the working portion ofthe treating catheter is located beyond the distal end portion 224 ofthe tube member. The operating physician can then treat the lesion 218using standard techniques with added back-up support on the guidecatheter 202, thereby providing an extra ability to push and advance thetreating catheter.

In general, the lumen 228, and hence the tube member 220, can be sizedand shaped to pass one or more interventional devices such as theguidewire and the treating catheter therethrough. The cross-sectionalshape of the lumen 228 can be similar to the cross-sectional shape ofthe guide catheter's main lumen 204. The outer diameter of the tubemember 220 can assume maximum cross-sectional dimensions that allow thetube member 220 to coaxially slide into and through the guide catheter202. In other embodiments, the outer cross-sectional dimensions of thetube member 220 can be less than the allowable maximum. For example, inan 8F guide catheter, the tube member 220 can have a 7F, 6F, 5F, 4F orlesser diameter. In some embodiments, a diameter of the lumen 228 of thetube member 220 is not more than one French size smaller than a diameterof the lumen 204 of the guide catheter 202. The length of the tubemember 220 can be substantially less than the length of the guidecatheter 202; however, the tube member 220 can be designed with anylength according to a desired application, such as about 6 cm-45 cm.

The push member 222 can be attached at least to the proximal end portion226 of the tube member 220 and can extend proximally from thisattachment to a handle member 230 accessible to an operating physicianoutside of a patient's body. The handle member 230 and the push member222 can allow the physician to position the tube member 220 between afirst position, entirely within the guide catheter 202, and theillustrated second position, in which the tube member's distal end 224extends beyond that of the guide catheter 202 and into the coronaryartery 210. The push member 222 can include one or more tubular bands270 or other means along its length to urge the member to one side ofthe guide catheter's inner wall surface 246, thereby providing a clearpath through the guide catheter and into the guide extension catheter202 for the guidewire 212 and treating catheter. This clear path canavoid or reduce the guidewire 212 becoming entangled with (e.g., wrappedaround) the push member 222 during use of the guide extension catheter202.

FIG. 3 illustrates a side view of a guide extension catheter 300partially positioned within a guide catheter 302. This side viewillustrates in greater detail the two primary components of the guideextension catheter 300—a relatively flexible elongate tube member 320and a push member 322. In certain embodiments, the push member 322 caninclude a plurality of segments or portions having different stiffnessand flexibility profiles to provide the guide extension catheter 300with a desired combination of pushing force and vessel placementcapabilities. In one embodiment, as shown in cross-sections at FIGS.4-6, the push member 322 can include three segments 334, 336, 338 havingdifferent stiffness and flexibility profiles: relative high stiffnessand low flexibility at a proximal end portion of the push member,relative medium stiffness and flexibility in an intermediate portion ofthe push member, and relative low stiffness and high flexibility at adistal end portion of the push member. In some embodiments, the lengthof the first segment 334 makes up between 50% to 90% of the entirelength of the guide extension catheter 300, the length of the thirdsegment 338 makes up between 2% to 10% of the catheter's length, and theremaining length can be attributed to the second segment 336. More orless segments of differing stiffness and flexibility profiles can alsobe used and accomplished through variation of one or more of materials,geometrical shapes or geometrical sizes of the push member 322.

The push member 322 can be an elongated solid wire of constant orvarying dimensions and can made of a polymeric or metallic material,such as high tensile stainless steel (e.g., 304V, 304L or 316LV), mildsteel, nickel-titanium alloys, nickel-chromium-molybdenum alloys,nickel-copper alloys, nickel-tungsten alloys or tungsten alloys. Thepush member 322 can be coated with a hydrophilic, silicone or otherfriction-reducing material. A handle member (FIG. 2) at the pushmember's proximal end can be formed of a polycarbonate material, forexample.

The tube member 320 can be formed from an inner polymer layer, an outerpolymer layer, and a reinforcement member (e.g., braid or coil) disposedbetween the polymer layers. The inner polymer layer can be composed of,or coated with, silicone, polytetrafluoroethylene (PTFE) or anotherlubricious material to provide a slippery surface for receivedinterventional devices. The outer polymer layer can include one or moreflexible materials, such as polyurethane, polyethylene or polyolefin ofsequentially diminishing durometers along the tube member's length, andit can be coated with a friction-reducing material (e.g., a hydrophilicmaterial) to facilitate insertion and trackability through vasculatureand a guide catheter. The reinforcing braid or coil can be formed ofstainless steel or a platinum alloy, for example, and can extend betweenthe polymer layers along at least a portion of the tube member's length.

A proximal end portion 326 of the tube member 320 can be eccentricallycoupled to a distal end portion 340 of the push member 322 at itsperiphery or circumference and can provide a smooth transition betweenthe members. The arrangement or configuration of this coupling can vary.For example, the tube member 320 can have an opening formed in itsperipheral wall and the push member 322 can be disposed within theopening. Inserting the push member 322 into the opening can result in amechanical coupling between the members and additional or alternativebonds (e.g., adhesive bonds, thermal bonds, welds, brazes, etc.) can beutilized. The distal end portion 340 of the push member 322 can beflattened to provide a larger surface area to secure to the tube member320. Coupling mechanisms facilitated by a third component 332 (e.g., ametal or polymer skived (slanted) collar or concave track) bondedbetween or integrated with the proximal end portion 326 of the tubemember 320 or the distal end portion 340 of the push member 322 are alsocontemplated. Metallic or polymeric structures forming the thirdcomponent 332 can become less stiff and more flexible in aproximal-to-distal direction to provide a gradual flexibility transitionbetween the more rigid push member 322 and the more flexible tube member320.

Markers on the push member 322 or the tube member 320 can allow anoperating physician to identify positioning of the guide extensioncatheter's components relative to patient anatomy, the guide catheter302, and any international devices used during a procedure. For example,one or more depth markers can be printed on an outer surface of the pushmember 322 and can be positioned at predetermined lengths relative to adistal end of the tube member 320. One or more radiopaque marker bandscan be positioned on the tube member 320. The marker bands can becomposed of tungsten, platinum or an alloy thereof and can have ametallic band structure. Alternatively, for space conservation reasons,the marker bands can be formed by impregnating portions of the tubemember 320 with a radiopaque filler material, such as such as bariumsulfate, bismuth trioxide, bismuth carbonate, powdered tungsten,powdered tantalum or the like. A first marker band can be positionedslightly distal to a fully-round entrance of the tube member 320 and asecond marker band can be positioned near the tube member's distal end,for example.

FIG. 4 illustrates a cross-sectional view of a proximal end portion 434of a push member 422, such as along line 4-4 of FIG. 3, within a guidecatheter 402. The cross-section can be defined by an arcuate firstsurface 444 configured to engage an inner wall surface 446 of the guidecatheter 402 along an arc length (l₁) (e.g., 0.030 in) defined by aguide catheter central angle (ζ) of at least 20 degrees, at least 30degrees, at least 40 degrees, at least 50 degrees or at least 60degrees, with greater arc lengths (l₁) associated with greater centralangles (α). The arcuate or curved shape of the first surface 444 followsthe inner wall surface 446 of the guide catheter 402 providing smoothrelative movements between the guide extension catheter and the guidecatheter. The arcuate shape of the first surface 444 can also help tomaximize axial or column strength of the push member 422 for forcetransfer from an operating physician to the rest of the guide extensioncatheter without reducing the effective delivery area 448 within theguide catheter 402 through which an interventional device can beadvanced. In an embodiment, the first surface 444 can have the same orsubstantially the same radius of curvature (r₁) as the guide catheter'sinner wall surface 446, such as a radius of curvature of about 0.035 in.

A second surface 450 of the proximal end portion's cross-section, whichis positioned opposite the first surface 444, can be flat orsubstantially flat and have a length (l₂) (e.g., 0.026 in) that is lessthan the arc length (l₁) of the first surface. The second surface 450can be spaced furthest from the first surface at its center point (c₂).In an embodiment, the center point (c₂) of the second surface 450 is atleast 0.010 in (e.g., 0.014 in) from a center portion (c1) of the firstsurface 444. In an embodiment, a distance between center points (c₁, c₂)of the first and second surfaces 444, 450 can be between 40-60% of thearc length (l₁) of the first surface.

The cross-section at the proximal end portion of the push member 422 canbe further defined by third and four arcuate surfaces 452, 454 thatconnect the first and second surfaces 444, 450. The third and foursurfaces 452, 454 can have a radius of curvature (r_(3,4)) less than theradius of curvature (r₁) of the first surface 444. In an embodiment, theradius of curvature (r₁) of the first surface (e.g., 0.035 in) is atleast three times greater than the radius of curvature (r_(3,4)) of thethird and fourth surfaces (e.g., 0.010 in).

It has been found that this cross-sectional configuration of theproximal end portion 434 of the push member 422 can be desirable for anumber of reasons. The configuration, which resembles a bread loaf inits cross-sectional shape, can increase the push force capability andthe torque control of the push member 422 as compared to a flatrectangular ribbon. Accordingly, greater axial and rotational forceapplied by the operating physician to the push member's proximal endportion 434 can be transmitted to the tube member. In this manner, thetube member can more reliably be urged through obstructions or into atortuous portion of the patient's vasculature.

FIG. 5 illustrates a cross-sectional view of an intermediate portion 536of a push member 522, such as along line 5-5 of FIG. 3, within a guidecatheter 502. As shown, the intermediate portion 536 can be circular oroval in cross-section and defined by a circumferential surface 537,which can reduce the tendency for a guidewire to become engaged with thepush member 522 during use. In an embodiment, the circumferentialsurface 537 has a diameter of about 0.013 in.

Alternatively, the intermediate portion 536 can be rectangular incross-section and defined by first, second, third and fourth flatsurfaces, or can be bread loaf in cross-section and defined by threearcuate surfaces and one flat surface similar to the proximal endportion. In these alternative embodiments, a distance change betweencenter points of the first and second surfaces at the push member'sproximal end portion (FIG. 4) to center points of the first and secondsurfaces at the push member's intermediate portion is less than adistance change between center points of the third and fourth surfacesat the push member's proximal end portion to center points of the thirdand fourth surfaces at the push member's intermediate portion.

As yet another alternative, the intermediate portion 536 can have across-section defined by arcuate first and second surfaces. An arcuatefirst surface can have the same or substantially the same radius ofcurvature as the guide catheter's inner wall surface. An arcuate secondsurface can extend from a first end of the first surface to a second endof the first surface. Regardless of shape, the cross-section of theintermediate portion 536 of the push member can define an area less thanan area of the cross-section of the proximal end portion (FIG. 4) of thepush member 522.

FIG. 6 illustrates a cross-sectional view of a distal end portion 638 ofa push member 622, such as along line 6-6 of FIG. 3, within a guidecatheter 602. The distal end portion 638 can be rectangular incross-section and defined by first, second, third and fourth flatsurfaces 656, 658, 660, 662. The cross-section of the distal end portion638 can define an area less than an area of the cross-section of theproximal end (FIG. 4) and intermediate (FIG. 5) portions of the pushmember 622. In an embodiment, the first and second surfaces 656, 658have a length of 0.020 in., and the third and fourth surfaces 660, 662have a length of 0.010 in. The cross-section of the stiffer proximal endportion can gradually transition along the length of the push member 622to the more flexible cross-section of the distal end portion 638, whichcan couple to a tube member 620. The flattened rectangular cross-sectionof the distal end portion 638 can provide sufficient attachment surfacearea to attach the push member 622 to the tube member 620.Alternatively, the distal end portion 638 can be bread loaf incross-section and defined by three arcuate surfaces and one flat orsubstantially flat surface similar to the proximal end portion.

FIGS. 4-6 illustrate that the push member 422, 522, 622 of a guideextension catheter can be designed to be sufficiently small taking uprelatively little space within the lumen of a guide catheter, whilestill being sufficiently sized and configured for exceptionalpushability and kink resistance when advancing the extension catheterduring an interventional procedure. Accordingly, use of the presentguide extension catheters allows for an interventional device to beadvanced through and beyond the guide catheter in order to reach adesired distal target location for intervention.

FIG. 7 illustrates a side view of a guide extension catheter 700positioned within a guide catheter 702 and used in conjunction with aguidewire 712 and a treating catheter 764. With the guidewire 712 andthe guide catheter 702 positioned as desired, a tube member 720 of theguide extension catheter 700 can be backloaded from its distal endportion 724 onto a proximal end of the guidewire 712 and advancedthrough a hemostasis valve coupled to the guide catheter 702. As shown,the tube member 720 of the guide extension catheter 700 can be advancedbeyond a distal end 716 of the guide catheter 702 under fluoroscopy.When so arranged, portions of the tube member 720 can engage an ostiumand extend within a portion of a coronary artery to help maintain theposition of the guide catheter 702 as the treating catheter 764 isadvanced.

FIG. 8 illustrates a cross-sectional view of a guide extension catheter800, a guidewire 812 and a treating catheter 864 within a guide catheter802, such as along line 8-8 of FIG. 7. It can be seen that use of thepresent eccentrically-positioned push member 822 to adjust a position ofa tube member 820 of the guide extension catheter 800 can provideseveral advantages. As a first example, the relatively small dimensionsof the push member 822 create low surface friction during itslongitudinal movement within the guide catheter 802. Low frictionalforce allows ease in extending and retrieving the tube member 820. Asanother example, the small cross-sectional dimensions of the push member822 do not significantly interfere with the delivery of the treatingcatheter 864 through the guide catheter 802.

Delivery of the treating catheter 764, 864 through the guide catheter702, 802 and into the tube member 720, 820 can be facilitated by aconcave track 732, 832 defining a partially cylindrical opening andhaving a length of about 1 cm to 18 cm. The concave track 732, 832 isaccessible from a longitudinal side defined transverse to a longitudinalaxis of the tube member 720, 820 and provides a larger area to receivean interventional device into the tube member than an area associatedwith an opening oriented perpendicular to the longitudinal axis of thetube member. Optionally, the concave track 732, 832 can be sized largerthan the tube member 720, 820 (e.g., 7F or 8F outer diameter for theconcave track and 6F outer diameter for the tube member) to moreeffectively align and funnel the treating catheter 764, 864 across thecoupling transition and into the tube member 720, 820. This larger sizeof the concave track 732, 832 can be accomplished by incorporating anickel-titanium alloy, for example, which can expand post-implant to asize of the guide catheter's inner wall surface.

The concave track 732, 832 can be positioned between or integrated withthe proximal end portion of the tube member 720, 820 or the distal endportion of the push member 722, 822. In an embodiment, a first segmentof the concave track 732, 832 can have an arcuate cross-sectional shapeextending for a length of at least 0.5 cm and radially extending 25% to40% of a cross-sectional circumference of the guide catheter 702, 802 orthe tube member 720, 820. A second segment of the concave track 732, 832can have a hemicylindrical cross-sectional shape extending for a lengthof at least 0.5 cm and radially extending 40% to 70% of across-sectional circumference of the guide catheter 702, 802 or the tubemember 720, 820.

In lieu of the concave track 732, 832, the proximal end portion 726 ofthe tube member 720, 820 can be partially (e.g., top half only) orcompletely radially flared to be larger in size than other portions ofthe tube member and coincide with the inner diameter of the guidecatheter 702, 802. The close fit between the flared proximal end portionand the guide catheter 702, 802 can be used to align and funnel thetreating catheter 764, 864, for example, from the guide catheter lumeninto the tube member lumen, as well as direct fluid injected through theguide catheter into the tube member lumen. The flare can be accomplishedby molding the tube member's 720, 820 proximal end portion or byincorporating a size- or shape-changing alloy (e.g., a nickel-titaniumalloy) into the tube member's 720, 820 proximal end portion.

EXAMPLES

The above Detailed Description is intended to be illustrative and notrestrictive. The above-described embodiments (or one or more features orcomponents thereof) can be used in varying combinations with each otherunless clearly stated to the contrary. Other embodiments can be used,such as by one of ordinary skill in the art upon reviewing the aboveDetailed Description. Also, various features or components have beengrouped together to streamline the disclosure. This should not beinterpreted as intending that an unclaimed disclosed feature isessential to any claim. Rather, inventive subject matter can lie in lessthan all features of a particular disclosed embodiment. Thus, thefollowing claim examples are hereby incorporated into the DetailedDescription, with each example standing on its own as a separateembodiment.

In Example 1, a guide extension catheter for use with a guide cathetercan comprise an elongate tube member and a push member eccentricallycoupled to the tube member. The tube member can define a lumen and havean outer diameter smaller than a lumen of the guide catheter. The pushmember can extend proximally from its point of coupling with the tubemember for slidably positioning the tube member within and partiallybeyond a distal end of the guide catheter. At least a proximal endportion of the push member can include a cross-section defined by anarcuate first surface, which is configured to engage an inner wallsurface of the guide catheter along an arc length defined by a guidecatheter central angle of least 20 degrees, and a second surface, whichis opposite the first surface and has a center point at least 0.010inches from a center point of the first surface.

In Example 2, the guide extension catheter of Example 1 can optionallybe configured such that the first surface of the push member's proximalend portion has the same radius of curvature as the guide catheter'sinner wall surface.

In Example 3, the guide extension catheter of Example 2 can optionallybe configured such that the cross-section of the proximal end portion ofthe push member is further defined by third and four arcuate surfacesthat connect the first and second surfaces. The third and four surfacescan have a radius of curvature less than the radius of curvature of thefirst surface.

In Example 4, the guide extension catheter of Example 3 can optionallybe configured such that the radius of curvature of the first surface isat least three times greater than the radius of curvature of the thirdand fourth surfaces.

In Example 5, the guide extension catheter of any one or any combinationof Examples 1-4 can optionally be configured such that the secondsurface is flat.

In Example 6, the guide extension catheter of any one or any combinationof Examples 1-5 can optionally be configured such that the push memberis solid.

In Example 7, the guide extension catheter of any one or any combinationof Examples 1-6 can optionally be configured such that an intermediateor distal end portion of the push member includes a rectangularcross-section defining an area less than an area of the cross-section ofthe proximal end portion of the push member.

In Example 8, the guide extension catheter of any one or any combinationof Examples 1-7 can optionally be configured such that an intermediateor distal end portion of the push member includes a circularcross-section defining an area less than an area of the cross-section ofthe proximal end portion of the push member.

In Example 9, the guide extension catheter of any one or any combinationof Examples 1-7 can optionally be configured such that an intermediateor distal end portion of the push member includes a cross-sectiondefined by an arcuate first surface, which has the same or substantiallythe same radius of curvature as the guide catheter's inner wall surface,and an arcuate second surface, which extends from a first end of thefirst surface to a second end of the first surface.

In Example 10, the guide extension catheter of any one of Examples 7, 8or 9 can optionally be configured such that the cross-sectional area ofthe distal end portion of the push member is less than thecross-sectional area of the intermediate portion of the push member.

In Example 11, the guide extension catheter of any one of Examples 7, 8or 9 can optionally be configured such that a stiffness of the pushmember's proximal end portion is greater than a stiffness of the pushmember's intermediate and distal end portions.

In Example 12, the guide extension catheter of any one or anycombination of Examples 1-11 can optionally be configured such that thearc length of the first surface is greater than a length of the secondsurface.

In Example 13, the guide extension catheter of any one or anycombination of Examples 1-12 can optionally further comprise one or morebands along the length of the push member to urge it to one side of theguide catheter's inner wall surface.

In Example 14, the guide extension catheter of any one or anycombination of Examples 1-13 can optionally be configured such that adiameter of the lumen of the tube member is not more than one Frenchsize smaller than a diameter of the lumen of the guide catheter.

In Example 15, the guide extension catheter of any one or anycombination of Examples 1-14 can optionally further comprise a concavetrack defining a partially cylindrical opening leading into the tubemember.

In Example 16, the guide extension catheter of Example 15 can optionallybe configured such that a first segment of the concave track includes anarcuate cross-sectional shape.

In Example 17, the guide extension catheter of Example 16 can optionallybe configured such that a second segment of the concave track includes ahemicylindrical cross-sectional shape.

In Example 18, the guide extension catheter of any one or anycombination of Examples 1-14 can optionally be configured such that aproximal end of the tube member is partially or completely radiallyflared.

In Example 19, the guide extension catheter of any one or anycombination of Examples 1-18 can optionally be configured such that aproximal end of the tube member is skived.

In Example 20, a guide extension catheter for use with a guide cathetercan comprise an elongate tube member and a lumenless push membereccentrically coupled to the tube member at a distal end portion. Thetube member can define a lumen and have an outer diameter smaller than alumen of the guide catheter. The push member can extend proximally fromits point of coupling with the tube member for slidably positioning thetube member within and partially beyond a distal end of the guidecatheter. A proximal end portion of the push member can include across-section defined by an arcuate first surface, which is configuredto engage an inner wall surface of the guide catheter, and an opposingsecond surface, which is spaced furthest from the first surface as itscenter point. One or both of an intermediate portion and the distal endportion of the push member can include a cross-section defined byopposing first and second flat surfaces and opposing third and fourthflat surfaces.

In Example 21, the guide extension catheter of Example 20 can optionallybe configured such that the proximal end portion of the push member hasa proximal stiffness and the distal end portion of the push member has adistal stiffness, which is less than the proximal stiffness.

In Example 22, the guide extension catheter of any one of Examples 20 or21 can optionally be configured such that the cross-section of the pushmember's proximal end portion transitions along the length of the pushmember to the cross-section of the push member's distal end portion.

In Example 23, the guide extension catheter of any one or anycombination of Examples 20-22 can optionally be configured such that theproximal end portion has a relatively low flexibility, the distal endportion has a relatively high flexibility, and the intermediate portionhas a middle flexibility between that of the relatively low flexibilityof the proximal end portion and the relatively high flexibility of thedistal end portion.

In Example 24, the guide extension catheter of any one or anycombination of Examples 20-23 can optionally be configured such that thecross-section of the push member's proximal end portion is furtherdefined by third and four arcuate surfaces that connect the first andsecond surfaces.

In Example 25, the guide extension catheter of Example 24 can optionallybe configured such that a distance change between center points of thefirst and second surfaces at the push member's proximal end portion tocenter points of the first and second surfaces at the push member'sintermediate portion is less than a distance change between centerpoints of the third and fourth surfaces at the push member's proximalend portion to center points of the third and fourth surfaces at thepush member's intermediate portion.

In Example 26, the guide extension catheter of any one or anycombination of Examples 20-25 can optionally be configured such that adistance between center points of the first and second surfaces at thepush member's proximal end portion is between 40%-60% of an arc lengthof the first surface at the push member's proximal end portion.

In Example 27, the guide extension catheter of any one or anycombination of Examples 1-26 can optionally be configured such that allcomponents or options recited are available to use or select from.

Closing Notes:

The present guide extension catheters and methods can provide support orguidance for an interventional device beyond the distal end of a guidecatheter. Additionally, the guide extension catheters can allow for theposition of the guide catheter to be maintained relative to an ostium orbranch of a target vessel during an interventional procedure. The guideextension catheters include a proximal push member and a distal tubemember extendible beyond the distal end of the guide catheter. Theconfiguration of the push member can provide an advantageous blend ofstiffness, flexibility and space conservation, such that an operatingphysician can push the guide extension catheters where desired withoutkinking or improper bending and without reducing the effective devicedelivery area through the guide catheter.

The above Detailed Description includes references to the accompanyingdrawings, which form a part of the Detailed Description. The DetailedDescription should be read with reference to the drawings. The drawingsshow, by way of illustration, specific embodiments in which the presentguide extension catheters and related methods can be practiced. Theseembodiments are also referred to herein as “examples.”

Certain terms are used throughout this patent document to refer toparticular features or components. As one skilled in the art willappreciate, different people may refer to the same feature or componentby different names. This patent document does not intend to distinguishbetween components or features that differ in name but not in function.For the following defined terms, certain definitions shall be appliedunless a different definition is given elsewhere in this patentdocument. The terms “a,” “an,” and “the” are used to include one or morethan one, independent of any other instances or usages of “at least one”or “one or more.” The term “or” is used to refer to a nonexclusive or,such that “A or B” includes “A but not B,” “B but not A,” and “A and B.”All numeric values are assumed to be modified by the term “about,”whether or not explicitly indicated. The term “about” refers to a rangeof numbers that one of skill in the art considers equivalent to therecited value (i.e., having the same function or result). In manyinstances, the term “about” can include numbers that are rounded to thenearest significant figure. The recitation of numerical ranges byendpoints includes all numbers and sub-ranges within and bounding thatrange (e.g., 1 to 4 includes 1, 1.5, 1.75, 2, 2.3, 2.6, 2.9, etc. and 1to 1.5, 1 to 2, 1 to 3, 2 to 3.5, 2 to 4, 3 to 4, etc.). The terms“patient” and “subject” are intended to include mammals, such as forhuman or veterinary applications. The terms “distal” and “proximal” areused to refer to a position or direction relative to an operatingphysician. “Distal” and “distally” refer to a position that is distantfrom, or in a direction away from, the physician. “Proximal” and“proximally” refer to a position that is near, or in a direction toward,the physician. And the term “interventional device(s)” is used toinclude, but is not limited to, guidewires, balloon catheters, stentsand stent catheters.

The scope of the present guide extension catheters and methods should bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled. In the appendedclaims, the terms “including” and “in which” are used as theplain-English equivalents of the respective terms “comprising” and“wherein.” Also, in the following claims, the terms “including” and“comprising” are open-ended; that is, a device or method that includesfeatures or components in addition to those listed after such a term ina claim are still deemed to fall within the scope of that claim.Moreover, in the following claims, the terms “first,” “second” and“third,” etc. are used merely as labels, and are not intended to imposenumerical requirements on their objects.

The Abstract is provided to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims.

What is claimed is:
 1. A guide extension catheter for use with a guidecatheter, the guide extension catheter comprising: an elongate tubemember defining a lumen and having an outer diameter smaller than alumen of the guide catheter; and a push member eccentrically coupledrelative to an axis of the elongate tube member and extending proximalof the elongate tube member for slidably positioning the elongate tubemember within the lumen, and partially beyond a distal end, of the guidecatheter, the push member comprising a proximal end portion and one ormore additional portions, the proximal end portion having a lengthforming between 50% and 90%, inclusive, of an entire length of the guideextension catheter, and having a cross-section defined by an arcuatefirst surface configured to engage an inner wall surface of the guidecatheter along an arc length and a non-arcuate second surface locatedopposite the arcuate first surface and including a center point that isspaced further away from the arcuate first surface than any other pointalong the non-arcuate second surface.
 2. The guide extension catheter ofclaim 1, wherein the one or more additional portions of the push memberhave a flexibility that is greater than a flexibility of the proximalend portion of the push member.
 3. The guide extension catheter of claim1, wherein the one or more additional portions of the push member have across-section defined by an arcuate first surface configured to engagethe inner wall surface of the guide catheter along an arc length and anon-arcuate second surface located opposite the arcuate first surfaceand including a center point that is spaced further away from thearcuate first surface than any other point along the non-arcuate secondsurface.
 4. The guide extension catheter of claim 1, wherein the one ormore additional portions of the push member include an intermediateportion and a distal end portion, the intermediate portion coupling theproximal end portion and the distal end portion of the push member. 5.The guide extension catheter of claim 4, wherein the distal end portionof the push member has a flexibility that is greater than a flexibilityof the intermediate portion of the push member.
 6. The guide extensioncatheter of claim 1, further comprising a coupling member securing thepush member to the elongate tube member.
 7. The guide extension catheterof claim 6, wherein the coupling member comprises a metallic orpolymeric structure having a flexibility less than a flexibility of adistal end portion of the elongate tube member.
 8. The guide extensioncatheter of claim 6, wherein the coupling member comprises a concavetrack defining a partially cylindrical opening for receiving a treatmentdevice into the elongate tube member.
 9. The guide extension catheter ofclaim 6, wherein the coupling member comprises a collar having a slantedopening.
 10. The guide extension catheter of claim 6, wherein thecoupling member provides a flexibility transition between the pushmember and the elongate tube member.
 11. The guide extension catheter ofclaim 1, wherein a proximal end of the elongate tube member includes anopening formed in its peripheral wall, and wherein a distal end portionof the push member is inserted into the opening resulting in amechanical coupling between the push member and the elongate tubemember.
 12. The guide extension catheter of claim 1, wherein theproximal end portion and the one or more additional portions of the pushmember comprise a polymetric material.
 13. The guide extension catheterof claim 1, wherein the proximal end portion and the one or moreadditional portions of the push member comprise stainless steel.
 14. Theguide extension catheter of claim 1, wherein the arc length is definedby a guide catheter central angle of at least 20 degrees.
 15. The guideextension catheter of claim 1, wherein the arcuate first surface of theproximal end portion of the push member has a radius of curvaturesubstantially the same as the inner wall surface of the guide catheter.16. The guide extension catheter of claim 15, wherein the cross-sectionof the proximal end portion of the push member is further defined byarcuate third and fourth surfaces that connect the arcuate first surfaceand the non-arcuate second surface, the arcuate third and fourthsurfaces having a radius of curvature less than the radius of curvatureof the arcuate first surface.
 17. The guide extension catheter of claim16, wherein the radius of curvature of the arcuate first surface is atleast three times greater than the radius of curvature of the arcuatethird and fourth surfaces.
 18. The guide extension catheter of claim 1,wherein the push member is lumenless.
 19. The guide extension catheterof claim 1, wherein the arc length of the arcuate first surface isgreater than a length of the non-arcuate second surface.
 20. The guideextension catheter of claim 1, wherein a diameter of the lumen of theelongate tube member is not more than one French size smaller than adiameter of the lumen of the guide catheter.
 21. The guide extensioncatheter of claim 1, wherein a proximal end of the elongate tube memberis at least partially radially flared.
 22. A method of performing acardiac intervention on a patient, the method comprising: advancing aguidewire through an aorta of the patient to an ostium; advancing aguide catheter having an inner lumen over the guidewire so that a distalend of the guide catheter is positioned near the ostium; and advancingan elongate tube member of a guide extension catheter over the guidewireand through the inner lumen of the guide catheter to position a distalend of the elongate tube member beyond a distal end of the guidecatheter and into the ostium, including applying a force to a pushmember that is coupled to, and extends proximally from, the elongatetube member, wherein applying the force to the push member includesengaging an arcuate first surface of the push member against an innerlumen wall of the guide catheter and positioning an opposing,non-arcuate second surface of the push member such that its midpoint isspaced further away from the arcuate first surface than any other pointalong the opposing, non-arcuate second surface.
 23. The method of claim22, further comprising delivering a treatment catheter over theguidewire, through the guide catheter and alongside the push member ofthe guide extension catheter, and into the elongate tube member of theguide extension catheter so that a working portion of the treatmentcatheter is extended beyond the distal end of the guide extensioncatheter, wherein a smallest effective lumen diameter through the guidecatheter and alongside the push member of the guide extension catheterand into the elongate tube member of the guide extension catheter forthe treatment catheter to pass is not more than one French size smallerthan a diameter of the inner lumen of the guide catheter.